Polypoid endometriosis of the Douglas pouch

Abstract

Polypoid endometriosis is a rare form of endometriosis that corresponds to a benign variant but which systematically mimics malignant tumors. Magnetic resonance imaging (MRI) is the preferred imaging modality for these lesions. We present herein a case of a 43-year-old female with recent pelvic pain and longstanding dyspareunia related to polypoid endometriosis of the Douglas pouch. MRI found an infiltrative lesion 6 cm in diameter with intermediate signal on T2-weighted imaging, cystic hemorrhagic spots, and fibrous surrounding rim of nodular portion. There was no functional sign of malignancy (no diffusion restriction, pronounced tumor enhancement, or metastasis). The patient underwent total abdominal radical colpohysterectomy with bilateral salpingectomy and ovarian transposition was performed. Histopathological examination found a multinodular endometrial-type polypoid mass arising from the serosa of the cervix, with cystic area and fibrous surrounding tissue. In the case presented, MRI findings were useful for preoperative diagnosis that altered patient management by supporting a complete but reasonable surgical resection that yielded relief of symptoms.

Keywords: Endometriosis; Magnetic resonance imaging; Neoplasm; Peritoneal diseases.

Fig. 1

A 43-year-old nulliparous woman with polypoid endometriosis of the Douglas pouch. A. Sagittal T2, B. axial T2 and C. axial T1 with fat saturation-weighted images show a heterogeneous T2 intermediate signal mass with cystic areas, some being hemorrhagic (black arrows). This reflects the presence of abundant dilated endometrial-like glands detected on histology (G). T2 and T1 hypointense septations and a peripheral hypointense rim-like alterations (white arrows) are present. D. Axial diffusion (b = 1000 s/mm²; left) and apparent diffusion coefficient (ADC) map (generated from b value of 0 and 1000 s/mm²; right) images show no restricted diffusion and high mean ADC value (measured in the largest nodular portion: 2.15 × 10⁻³ mm²/s). E. Axial subtraction of late-phase postcontrast T1-WI shows weak enhancement of the mass compared with that of uterine myometrium (arrow) and mild enhancement of septations and peripheral rim. F. Sagittal view (photograph) of the hysterectomy piece shows a reddish mass (white arrows) infiltrating the pouch of Douglas and the posterior cervix. Note the adhesive epiploic appendage of the rectosigmoid (black arrow). G. Macroscopy (photograph) shows a multinodular whitish-yellow polypoid mass arising from the serosa of the cervix (green coloration indicating the anterior part of the cervix), with cystic area (black arrows) and fibrous surrounding tissue (white arrows) corresponding to fibrous structures found on MRI (panels A, B, C, and E). H. Histopathological photomicrograph at 1.5x magnification (hematoxylin-eosin-saffron stain) shows numerous endometrial glands with cystic dilatation (black arrows) and some focal polypoid protrusions at the serosal surface (white arrows).